SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4de0e6adc0292ec43546df2a79e86663348aa40f96b781dc9064e397eaccc062' 
  AND token = '1JArqehcKhpyTz8JqSKxiZ9GH7BXE+j3sFg6llcdsQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}